Heat assisted magnetic recording (HAMR) is one type of data storage that has been proposed as a solution for increasing the areal density of recording data. HAMR generally refers to the concept of locally heating a recording medium to reduce the coercivity of the medium so that an applied magnetic writing field can more easily direct the magnetization of the recording medium during the temporary magnetic softening of the recording medium caused by the heat source. HAMR allows for the use of small grain media, which is desirable for recording at increased areal densities, with a larger magnetic anisotropy at room temperature to assure sufficient thermal stability.
HAMR media usually requires a well-controlled thermal profile in order to achieve high track density and provide a good thermal gradient for recording. The use of a heat sink layer in the media has been proposed in order to conduct or direct heat away from the recording layer after writing to limit thermal erasure. However, the heat sink not only conducts heat vertically but also conducts heat laterally. Therefore, employing a media having a heat sink layer can result in the media exhibiting lateral thermal spreading. This lateral thermal spreading during the writing process limits the track density and the size of data bits.
In order to achieve additional increases in data storage capacities, there remains a need for further reduction in the size of data bits written in storage media.